One of causes of noise generated in a pneumatic tire is cavity resonance sound associated with vibration of the air filled inside the tire. When a tire is rolled, the air inside the tire is vibrated by the vibration of the tread portion due to irregularities of a road surface, which generates the cavity resonance sound.
As a method of reducing noise generated by the cavity resonance phenomenon as described above, it has been proposed that a noise absorbing member is disposed in a cavity portion formed between a tire and a rim of a wheel (refer to Patent Document 1, for example). However, when the noise absorbing member is attached to the outer peripheral surface of the rim of the wheel, the noise absorbing member interferes with the operation of mounting the pneumatic tire on the rim. On the other hand, when the noise absorbing member is attached to the inner surface of the tire, there is a problem in the durability. In addition, when a noise absorbing member formed of a porous material, such as a polyurethane foam, is fixed to the inner surface of the tire with a rubber adhesive agent or an adhesive tape, the noise absorbing member sometimes drops off from the inner surface of the tire due to the insufficient adhesive force.
Patent Document 1; Japanese patent application Kokai publication No. Sho 64-78902